package dp;

/**
 * Created with IntelliJ IDEA.
 * Description: 62. 不同路径
 * User: Li_yizYa
 * Date: 2025/7/1
 * Time: 14:52
 */
public class Solution4 {
    /**
     * 一维 dp
     * @param m
     * @param n
     * @return
     */
    public int uniquePaths1(int m, int n) {
        if (m == 0 || n == 0) {
            return 0;
        }
        int[] dp = new int[n];
        for (int i = 0; i < n; i++) {
            dp[i] = 1;
        }
        for (int i = 1; i < m; i++) {
            for (int j = 1; j < n; j++) {
                dp[j] += dp[j - 1];
            }
        }
        return dp[n - 1];
    }
    /**
     * 二维 dp
     * @param m
     * @param n
     * @return
     */
    public int uniquePaths(int m, int n) {
        if (m == 0 || n == 0) {
            return 0;
        }
        int[][] dp = new int[m][n];
        for (int i = 0; i < m; i++) {
            dp[i][0] = 1;
        }
        for (int i = 0; i < n; i++) {
            dp[0][i] = 1;
        }
        for (int i = 1; i < m; i++) {
            for (int j = 1; j < n; j++) {
                dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
            }
        }
        return dp[m - 1][n - 1];
    }
}
